1. Field of the Invention
This invention relates to an assembly for fastening an inner ring of an anti-friction bearing upon a shaft.
2. Description of the Prior Art
Eccentric cam locking collars have been used to fasten an inner ring of an anti-friction bearing to a rotatable shaft. Such collars have a tapered eccentric counterbored recess surface that engages a tapered eccentric extended surface at one end of the inner ring, and these surfaces function as mating cams. Rotation of the collar, relatively to the inner ring, causes a self-locking action, of the collar and inner ring, to the shaft. The locking force is distributed to the shaft, in a narrow band surrounding the shaft where the collar and ring overlap. The high pressure along the narrow band, about the shaft, often results in fretting corrosion problems. Such cam locking collars are shown in U.S. Pat. No. 1,650,573 that issued to Searles on Nov. 22, 1927; U.S. Pat. No. 1,821,877 that issued to Brown on Sept. 1, 1931; and U.S. Pat. No. 1,835,991 that issued to Runge on Dec. 8, 1931.
Locking collars can be eliminated by the use of eccentric cam sleeves or segments that fit within eccentric grooves in the bore portions of inner rings. Such sleeves and segments are shown in U.S. Pat. No. 2,038,121 that issued to Miller on Apr. 21, 1936; U.S. Pat. No. 2,100,725 of Styrl that issued on Nov. 30, 1937; U.S. Pat. No. 3,007,753 that issued to Potter on Nov. 7, 1961; and U.S. Pat. No. 3,920,342 that issued to Warda on Nov. 18, 1975. Only the Potter patent suggests that the locking ring, carried by the shaft within the inner bearing ring, has a bore of lesser unstressed diameter than the shaft diameter to enable the ring to grip the shaft, and the ring shown in this patent is a continuous ring.
U.S. Pat. No. 2,228,282 that issued to Miller on Jan. 14, 1941, shows a tapered sleeve that is split longitudinally for locking a bearing ring upon a shaft. This patent discloses that if the sleeve bore is undersized with respect to the shaft, it is, of course, self-holding on the shaft. Since the sleeve is tapered, relative axial movement between the complemental tapered portions of the sleeve and the bearing ring is required for increasing frictional engagement, to bind the ring and sleeve upon the shaft. The sleeve does not fit in a groove that extends radially outward and circumferentially about an axially intermediate portion of the ring bore.
When a sleeve having an eccentric external contour is fitted into an eccentric groove that extends circumferentially about an axially intermediate portion of a ring bore, clearance and alignment problems are often encountered. It is desirable to minimize clearances between the shaft, the sleeve, and the ring, for reducing the relative rotation required to lock the sleeve upon the shaft. When such clearances are minimized, the eccentric central axes of the groove bottom and the external contour of the sleeve must be aligned radially with each other from the central axis of the ring bore, to enable the shaft to be slipped axially through the sleeve bore. The sleeve must be compressed radially to fit through the ring bore to the eccentric groove. Upon expansion of the sleeve to an unstressed condition within the groove, the sleeve should frictionally grip the shaft to prevent the shaft from turning within the sleeve bore. Slippage of the shaft within the sleeve bore would not provide relative rotation between the sleeve and the ring for tightening the sleeve upon the shaft.